Hello everyone,

I am working on a 1920 house that has balloon frame construction. It also has horizontal tongue and grove, or ship lap. The studs are made up of rough sawn true 2x4's and also 4x4's. The 4x4's are mainly located where the doors are. This is also 24" on center framing.

I need to insulate the house as there is none in the walls and only has 2" thick rockwool blocks in the attic.

I am doing a major rehab on this house and mainly by myself with some off and on of a retired painter/helper. The best time to have put insulation in the walls would have obviously been when I was replacing the wood lap siding outside. However, due to the lack of skilled help, and the need to close a whole the same day it was created, this was not an option during storm season. I was also unsure of how the wiring and other things were going to be done at this point. The condition of this house was very rough, and I needed to get the outside work done first.

I would like to take advantage of the ship lap walls inside as people are paying lots of money just to get this look that I have originally. These boards are old and will likely break trying to remove them. I have a friend who does handyman work and him and I both agree that these boards are part of the structural integrity of this house, and thus should not be removed. Also, the way the house is built, the door and window trim were put directly onto the studded wall and then the ship lap, which was the finished wall originally, butted up against them. This leaves very little reveal of the door and window trims and thus does not leave room to sheetrock over the ship lap walls without having to do something with the trim.

With all of this in consideration, this is making it difficult to figure out the best approach in insulating this house. I have called a few companies to get estimates on blowing insulation in the walls and attic. However, it appears that most of these companies no longer blows insulation in the walls but rather want to inject foam.

I have a few concerns with that.

1) they want to drill holes in the ship lap in several places. They also mentioned removing some siding and going in from the outside. I am refusing that method as I have painstakingly predrilled every hole and hand nailed every nail into my new cedar siding.

2) due to the nature of this ship lap and its age, there are some gaps between some boards, thus I am concerned about the foam coming out between the boards.

3). The house is really old and I am concerned with its ability to breath after the fact and thus causing problems.

I have brought to their attention that the tops of the walls are completely open in the attic, but they don't want to try and go in from the top. They all know that they will have to block the bottom of these walls as they are also open in the crawl space due to the nature of the balloon frame construction.

So far, I have had 2 companies tell me that they don't blow insulation in the walls anymore. I have gotten a quote from one company that wants to drill the holes and inject the foam. About $4100.00 just to do the walls.

I had another guy tell me that they also mainly do foam and try not to do the other. He mentioned spraying the attic rafters with closed cell foam, to include blocking off the gable vents, spraying those, spraying to block the ridge vent, of which I recently had installed, as suggested by the roofer, removing the insulation on the attic floor and not putting any back down on the floor. He said that he would not worry about doing the walls at that point. He said this is called "heat stacking". I tried to look it up but can't find any reference to this as far as house insulating goes. It doesn't make since to me anyway. Why would I want to throw heat in the attic and hope that it circulates back down?

This same guy was supposed to give me a quote both ways, but I only see the quote for removing the old insulation on the attic floor, vacuuming the floor clean, blowing fiberglass in the walls and in the attic at a price of over$8000.00.

I have another person coming tomorrow and another December 1st.

With all that said, what is the suggestion of the group here, especially those who are contractors or handymen?

Do any of you know what the one guy was referring to when he mentioned heat stacking?

Would it be wise to try and remove the planks on the wall?

How would you insulate the walls?

How would you insulate the attic?

Does it make since that the gable vents and ridge vent be sealed shut with foam?

Thank you for your time.

6x6

I think your ideas are right and the other people are just trying to do the easiest thing they can to maximize their fees.

I would not mess with foaming the attic, especially closing off the vents you already paid to do. Also, I would not foam the walls, especially because of the old shiplap on them.

What I would do is block the bottoms of the walls like you said, then I'd go to Home D and get some regular fiberglass insulation and a machine that chops it up and pumps it which they will let you use if you buy the insulation.

Then I'd gently remove the top shiplap board in each room and fill the walls up to that board and then replace it. Then I'd go to the next floor and do the same until I got to the top of the wall, than I'd close up the top. If I was worried about the insulation settling, I'd pop off the bottom shiplap on each floor and add a block between the studs to reduce the weight of the insulation in each bay, top to bottom.

I think you'll find the cost of the insulation and the free loan of the machine to be way less than those bids.

It sure would help if you could post some pictures of the attic access especially at the tops of the stud bays, the basement showing the bottoms of the stud bays, the interior of the exterior walls and some of the exterior walls. That being said it's very possible that you could blow cellulose, chopped fiberglass or a combination of them both from the attic.

Presuming that you can successfully snake the insulation hose down each stud bay from the attic you should be able to do a majority of the bays without too many issues. I've done similar insulating a 1 story building that I didn't want to make holes in either the interior or exterior wall faces. Of course you still need to figure out how to insulate above & below the windows where there are some sort of horizontal headers.

To block the bottom of each stud bay I would stuff some Roxul up each one from the basement. You might also use pieces of 1" or 2" rigid foam that is sealed in place with a bit of spray foam to prevent the blown in insulation from spilling out into the basement / crawlspace.

If this is a 2 story building you could access the space below the first floor windows from the basement. To access the top of the first floor windows & the bottom of the second floor windows would require some creativity. It might be possible to either remove the baseboard on the second floor exterior walls to gain access to both the space below the second floor windows & the tops of the first floor windows.

I doubt very much that you will find an insulation company willing to take the extra effort involved in saving your ship lapped paneling. These companies would prefer doing more conventional jobs where they can just blow & go.

Is your siding outside painted now? It is still an option to do the blown in insulation that way. Look up a video on this old house and it has all the details. You would 'plug' the holes w/ wood circles and paint over them.

I agree with most of what Richard says. For the top board of each floor you could cut a thin strip of fiberglass batting and install it once the rest is blown in the walls. Never heard of heat stacking.

In general I like cellulose better due to higher insulation value per inch plus it doesn’t itch.

Before you blow in, you can seal gaps in interior boards with a paintable caulking, or better yet a very high quality elastomeric compound commonly used for around concrete pads as long as you can find one thick enough to use on horizontal surfaces….most of them are self leveling and therefore may run down the walls. Make sure anything used is paintable.

I was told in home inspector training that about 75% of heat loss is through the attic, not the walls…so I’d focus more effort there. In fact, of the remaining amount leaving through the walls, most of THAT is through the windows. This doesn’t suggest you ignore the walls, just downplay it somewhat.

I don’t know as much about spray foam but I don’t like the idea of spraying it over things like wires, ducts, and plumbing pipes.

I think that the second contractor's price of $8000.00 would be viable. How big is the house? The project sounds interesting.

I recently put R-38 for ceiling and exterior walls in a property in San Jose, CA. I wanted to use roll-in Roxul/Rockwool, but the price was nearly 35% more and was backordered for several weeks.

6 bye you have a dilemma. A fork in the road.

what exactly are your trying to accomplish? Fuel savings? Total or near total insulation coverage-- but to what end?

You can not get 100% insulating without removing either the inside or outside stud sheathing. As you say pulling it off, with the age of the wood, would deteriorate the wood. So thats unacceptable.

No matter what you do you will not get 100% efficiency. The foam technique will give you the best overall R value. Cellulose will settle over time so your back to not covered all the way.

I sold a 1930s home because I felt it would always be a maintenance pig.

Thank you everyone for the replies.

For a bit of un update:

I got another estimate today. Spraying foam in the walls $4792.00. Blowing fiberglass in attic to 13 inches to achieve R38 $2240.00.

They do not want to insulate the walls from the attic.

None of these companies thus far will spray in cellulose. They all say that it is a terrible product as it settles and is a fire hazard. From what those of you have said, it sounds like that it is not such a fire hazard and is good at deterring bugs. I didn't know that bugs liked fiberglass, but a pest control guy told me that cellulose would kill the bugs or keep them out.

I have, and am still, rewiring the whole house and also replacing all of the plumbing. This is a major rehab as I don't want to have constant maintenance, although I am sure there will be some.

I placed my hand on the ship lap wall this morning while it was about 29 degrees outside, and the walls did not feel very cold, nor did I feel any drafts. The inside of the house was around 42 degrees. I had 1 milkhouse heater going overnight.

I am considering not insulating the walls and was thinking this morning about using the machine from HD and blowing in the attic. I have also considered using batting in the attic and doing it as Robert, Ontario described by laying it in between the joist and then another layer going on top in the other direction. This would probably be lass messy.

If I install the insulation in the attic myself, would you remove the old rockwool insulation or just go over top of it? Obviously, over the years, there are some roofing debruise and general dirt on top of the rockwool.

I am getting another estimate on December 1st from a fireplace company, and they will be giving me an estimate on repairing the fireplaces as well.

Like Vee said, make SURE you have all your new wiring and plumbing in place before insulating!!

If you choose DIY blown insulation, here's a tip that could save you 33 percent:

Lowes sells pink bulk insulation for $XX per bag. IF YOU PURCHASE AT LEAST 30 BAGS, the cost is one third less, AND you get the loan of the blower for free. You can return 25 bags if you only need 5. With this project, you will need a lot more than that.

The key to a successful cellulose installation is to make sure that you dense pack the wall cavities. I have my own machine & regularly used it to dense pack cellulose from the interior of my units. Any cells that you purchase will have a treatment added to prevent burning as well as to lessen the chance of rodents nestling. The key thing is to determine the volume of the stud bays & use this to calculate how much cells you should be blowing into each bay.

With a q quick search you should be able to find lots on info on dense packing cellulose. This articel is pretty good.

I no longer let roofers talk me into ridge vents after my house got colder following that installation. I sold that one anyway. They are just covering their butts so their roofing product doesn't curl up early while still warrantied.

So there are people, at least one anyway, around here who will blow in insulation. I needed a porch roof done and the guy will only come for a minimum of $1,200 because there is so much set up time for that. It's a very small area so I declined that.

I am looking at an external system from a company called Sto for the outside of my brick colonial home and will talk to the sales guy on Monday. You don't want that because of your cedar that you applied but it's out there in case you or anyone has another issue. It's about five layers of stuff and the last layer would be fake brick instead of the actual brick of the house. I have plaster walls inside.

When I went to sell one house the realtor made sure that there was no "foam" in there. Some foam is full of formaldehyde and is very toxic and would have to be removed before closing. I didn't have any of that thankfully.

I like blowing because it assures no gaps between batts. Yes it’s messier but goes much faster once set up. Need 2 people…one to fill hopper and one to blow. Prep the attic by making some cheap sticks about 20” long and marking them with big numbers every 2”, then nail or screw those to ceiling joists in various areas….then use these as you blow in to know your depth and evenness without stopping to measure. For a 1,000 sqft attic, once it’s prepped and I start blowing, I can do the entire space in less than an hour depending on roof pitch (low slope Roos are harder because u have to lay on your stomach).

Don’t forget to ensure you have ventilation….preferably both bottom and topside…but often in very old homes they have no bottom side….you may have to add it and use rafter vents to prevent new insulation from blocking the vents…or use gable end vents as a solution. Without proper venting you’ll get ice damming, condensation, and other issues.

Before you sided the house you should have wrapped it with high density foam. Yank off the ship lap and bat the house.